| Message ID | 20231019104211.13769-2-johan+linaro@kernel.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Kalle Valo |
| Headers | show |
| Series | wifi: ath11k: fix event locking | expand |
On 10/19/2023 3:42 AM, Johan Hovold wrote: > The ath11k active pdevs are protected by RCU but the temperature event > handling code calling ath11k_mac_get_ar_by_pdev_id() was not marked as a > read-side critical section as reported by RCU lockdep: How do I enable this? Just enable CONFIG_PROVE_RCU? Of course I'd also need to exercise the code path... > > ============================= > WARNING: suspicious RCU usage > 6.6.0-rc6 #7 Not tainted > ----------------------------- > drivers/net/wireless/ath/ath11k/mac.c:638 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > rcu_scheduler_active = 2, debug_locks = 1 > no locks held by swapper/0/0. > ... > Call trace: > ... > lockdep_rcu_suspicious+0x16c/0x22c > ath11k_mac_get_ar_by_pdev_id+0x194/0x1b0 [ath11k] > ath11k_wmi_tlv_op_rx+0xa84/0x2c1c [ath11k] > ath11k_htc_rx_completion_handler+0x388/0x510 [ath11k] > > Mark the code in question as an RCU read-side critical section to avoid > any potential use-after-free issues. > > Fixes: a41d10348b01 ("ath11k: add thermal sensor device support") > Cc: stable@vger.kernel.org # 5.7 > Signed-off-by: Johan Hovold <johan+linaro@kernel.org> > --- > drivers/net/wireless/ath/ath11k/wmi.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/net/wireless/ath/ath11k/wmi.c b/drivers/net/wireless/ath/ath11k/wmi.c > index 23ad6825e5be..980ff588325d 100644 > --- a/drivers/net/wireless/ath/ath11k/wmi.c > +++ b/drivers/net/wireless/ath/ath11k/wmi.c > @@ -8383,6 +8383,8 @@ ath11k_wmi_pdev_temperature_event(struct ath11k_base *ab, > ath11k_dbg(ab, ATH11K_DBG_WMI, "event pdev temperature ev temp %d pdev_id %d\n", > ev->temp, ev->pdev_id); > > + rcu_read_lock(); > + > ar = ath11k_mac_get_ar_by_pdev_id(ab, ev->pdev_id); > if (!ar) { > ath11k_warn(ab, "invalid pdev id in pdev temperature ev %d", ev->pdev_id); aren't you missing an unlock() in this error path? perhaps have a goto cleanup that does both the unlock() and the kfree()? > @@ -8392,6 +8394,8 @@ ath11k_wmi_pdev_temperature_event(struct ath11k_base *ab, > > ath11k_thermal_event_temperature(ar, ev->temp); > > + rcu_read_unlock(); > + > kfree(tb); > } >
On 10/19/2023 8:04 AM, Jeff Johnson wrote:
> perhaps have a goto cleanup that does both the unlock() and the kfree()?
or goto exit to be consistent with others, including the DFS radar event
On Thu, Oct 19, 2023 at 08:04:55AM -0700, Jeff Johnson wrote: > On 10/19/2023 3:42 AM, Johan Hovold wrote: > > The ath11k active pdevs are protected by RCU but the temperature event > > handling code calling ath11k_mac_get_ar_by_pdev_id() was not marked as a > > read-side critical section as reported by RCU lockdep: > > How do I enable this? Just enable CONFIG_PROVE_RCU? Yeah, via CONFIG_PROVE_LOCKING. > Of course I'd also need to exercise the code path... Right, this one I hit when reading out the sensor temperature (e.g. using lm_sensors). > > + rcu_read_lock(); > > + > > ar = ath11k_mac_get_ar_by_pdev_id(ab, ev->pdev_id); > > if (!ar) { > > ath11k_warn(ab, "invalid pdev id in pdev temperature ev %d", ev->pdev_id); > > aren't you missing an unlock() in this error path? > > perhaps have a goto cleanup that does both the unlock() and the kfree()? Bah, I am, thanks for catching that. Spent too much time on scanning for further instances that I didn't check the first one properly. Sorry about that. Will send a v2. Johan
diff --git a/drivers/net/wireless/ath/ath11k/wmi.c b/drivers/net/wireless/ath/ath11k/wmi.c index 23ad6825e5be..980ff588325d 100644 --- a/drivers/net/wireless/ath/ath11k/wmi.c +++ b/drivers/net/wireless/ath/ath11k/wmi.c @@ -8383,6 +8383,8 @@ ath11k_wmi_pdev_temperature_event(struct ath11k_base *ab, ath11k_dbg(ab, ATH11K_DBG_WMI, "event pdev temperature ev temp %d pdev_id %d\n", ev->temp, ev->pdev_id); + rcu_read_lock(); + ar = ath11k_mac_get_ar_by_pdev_id(ab, ev->pdev_id); if (!ar) { ath11k_warn(ab, "invalid pdev id in pdev temperature ev %d", ev->pdev_id); @@ -8392,6 +8394,8 @@ ath11k_wmi_pdev_temperature_event(struct ath11k_base *ab, ath11k_thermal_event_temperature(ar, ev->temp); + rcu_read_unlock(); + kfree(tb); }
The ath11k active pdevs are protected by RCU but the temperature event handling code calling ath11k_mac_get_ar_by_pdev_id() was not marked as a read-side critical section as reported by RCU lockdep: ============================= WARNING: suspicious RCU usage 6.6.0-rc6 #7 Not tainted ----------------------------- drivers/net/wireless/ath/ath11k/mac.c:638 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 no locks held by swapper/0/0. ... Call trace: ... lockdep_rcu_suspicious+0x16c/0x22c ath11k_mac_get_ar_by_pdev_id+0x194/0x1b0 [ath11k] ath11k_wmi_tlv_op_rx+0xa84/0x2c1c [ath11k] ath11k_htc_rx_completion_handler+0x388/0x510 [ath11k] Mark the code in question as an RCU read-side critical section to avoid any potential use-after-free issues. Fixes: a41d10348b01 ("ath11k: add thermal sensor device support") Cc: stable@vger.kernel.org # 5.7 Signed-off-by: Johan Hovold <johan+linaro@kernel.org> --- drivers/net/wireless/ath/ath11k/wmi.c | 4 ++++ 1 file changed, 4 insertions(+)